The present invention relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides drainage of a heavy oil reservoir via a generally horizontal wellbore.
It is well known that extensive heavy oil reservoirs are found in formations comprising unconsolidated, weakly cemented sediments. Unfortunately, the methods currently used for extracting the heavy oil from these formations have not produced entirely satisfactory results.
Heavy oil is not very mobile in these formations, and so it would be desirable to be able to form increased permeability planes in the formations. The increased permeability planes would increase the mobility of the heavy oil in the formations and/or increase the effectiveness of steam or solvent injection, in situ combustion, etc.
However, techniques used in hard, brittle rock to form fractures therein are typically not applicable to ductile formations comprising unconsolidated, weakly cemented sediments. Therefore, it will be appreciated that improvements are needed in the art of draining heavy oil from unconsolidated, weakly cemented formations.